George Clooney is excited about playing an idiot in the Coen Brothers' latest movie, Hail, Caesar!

Since it was first pitched to him back in 1999 - "It's an old Hollywood story and you play a real idiot movie star" - George Clooney was in.

Since then, the 54-year-old US actor would say it was his next movie at every press opportunity - till he pretty much embarrassed Oscar-winning brothers Joel and Ethan Coen into completing the screenplay.

Opening here tomorrow, Hail, Caesar! is an affectionate look at the studio system of the Golden Age of Hollywood in the 1950s where stars were under contract with ironclad "moral" clauses. The studios decided their careers, monitored their behaviour and suppressed their scandals.

They had "fixers" - men who bought off law enforcement, planted misleading stories in the media and protected the reputations of the stars by all means.

No. When Joel and Ethan write parts for me, they never are the brightest (laughs) - roughly what they think of me in general. When I did O Brother, Where Art Thou? (2000), the first film I did with them, I played him like an idiot on the first day of shooting. They said, "No, you are the smartest guy in the room." Since then, for their films, I have done it as if he is the smartest guy in the room.

You have no wardrobe changes in this movie, wearing your Roman costume the whole time.

It's a nice skirt, isn't it? There were times where I was getting fitted and I'd go, "This could be the one that finally ends my career." Joel and Ethan would come into the wardrobe fitting and just start laughing.

Would you survive the kind of system in Hail, Caesar!?

Some actors of that era were just starting to break away from their contracts. Mostly women, the Bette Davises of the world. I would like to think of myself as someone who would work in something other than what the studio asked me to do.

After a certain Batman movie (Batman & Robin in 1997), I realised that if I were going to get blamed for a movie, it should be my decision and not somebody else's.

But I will say this. For 20 years, I was at Warner Bros a lot and Warner is an old studio. The guys I worked with had been there since the '50s. They would tell me stories about old directors, so I had a sense of what it was like to belong to a studio without the shackles of having to do everything as asked. I loved that, there was a sense of camaraderie.

What are the Coen brothers like on the set?

They work very quickly. They do only what they need. The dialogue never changes from the minute you get the script.

The brothers stand at the monitor by the camera and laugh way too loudly. I always think, "Jesus, these guys are ruining their own picture."

I have never seen it tense, I have never heard them raise their voices. I try to pit them against each other but they don't disagree on anything.